This invention relates to controllers or interfaces between signal sending units and signal receiving devices, and in particular to controllers employing multiplexed fiber optic transmission of the necessary signals, and the accompanying conversions and multiplexing from original electrical signals to optical signals and back to electrical signals.
Certain types of equipment employ electrical devices, such as motors and solenoids, which perform various functions and which are selectively energizable by means such as relays. These relays are often controlled by digital control signals provided over electrically conducting wires, either from an electronic computer or from some other type of signal generating control, such as a human operator. In addition, these devices experience conditions which require monitoring and possibly response by the computer or the operator, in effect evidencing a need to transmit data back to the computer or the operator.
For example, certain types of commercial and military aircraft of advanced design employ relay-controlled electrical load devices, such as motors located in various separated parts of the aircraft, which are energizable in response to switches operated by a pilot. In addition, such devices are commonly energizable according to commands, generally low power digital electrical signals, from a control computer, which may be remotely situated in the cockpit. In turn, these devices may experience over-current conditions, or for some other reason be forced to trip to an open state, and the operator or computer need to be informed of these conditions so as to enable a responsive action. Further, the operator or computer even needs to be aware of the state of the contacts, that is, whether they are open or closed. Hence control signals need to flow both from and to the operator or computer. In the past, these control signals have been transmitted via individual wires, usually at least one pair of wires for each of the devices to be controlled. However, this arrangement of at least a separate pair of wires for each device to be controlled had the undesirable effect of adding a substantial amount of weight to the aircraft for each controlled device, in addition to the problems of control cable routing and mounting competition for the wiring space within an aircraft.
This invention relates to improvements to the devices set forth above and to solutions to the problems raised thereby.